A common annoyance with conventional eyewear frames is that the frames slip along the nose of a wearer after a prolonged period of use. This is caused, for example, by spreading of temples.
Attempts have heretofore been made to incorporate means for applying a suitable amount of temple pressure on the head of a wearer to provide a comfortable and secured fit. Many of such means rely on leaf springs disposed on hinges between a lens frame and temples so as to urge the temples toward their folded or closed position. For example, U.S. Pat. No. 3,145,254 discloses a spring connection between a lens frame and each temple. The spring connection includes a U-shaped leaf spring disposed in each lateral end of the lens frame, and a temple insert disposed in one end of the temple and having an eccentric bifurcated portion. The eccentric bifurcated portion of the temple insert and the leaf spring are operatively associated to urge the temple against the head of a wearer. U.S. Pat. No. 3,654,376 discloses pressure means attached to each temple. The pressure means includes a resilient body snugly fit over one end of the temple, and an elongated resilient flat spring extending from the resilient body. The flat spring is engaged with each lateral end of the lens frame to exert a pressure on the temple to urge it toward its closed position.
A problem with the leaf springs is that repeated deformation of the leaf springs results in lowering of stress or spring resiliency. Another problem is that the leaf springs are visible at the external surface of eyewear and thus, disrupt esthetic appearance of the eyewear.
Accordingly, it is an object of the present invention to provide a hinge system for eyewear which can urge temples inwardly toward the head of a wearer to better retain the eyewear in the proper position on the wearer.
It is another object of the present invention to provide a hinge system for eyewear which can provide improved appearance and durability.